On 24/04/20 10:54 am, Markus Gothe wrote: > It's not required per se for an application. > > But you would need to relink your binaries with '-z,noexecstack' to turn > it off. > > //M So I've been trying to set CONFIG_EXTRA_LDFLAGS="-z,noexecstack" in my .config but it doesn't seem to make it through to the final link command. Is CONFIG_EXTRA_LDFLAGS expected to work?
> > On 2020-04-24 00:25, Chris Packham wrote: >> On Fri, 2020-04-24 at 00:08 +0200, Markus Gothe wrote: >>> Background: The executable stack is needed for MIPS and the FPU >>> (which >>> decodes any unknown instruction as well). >>> >>> There have been some patches floating around to fix this behavior >>> since >>> Linux 3.12 so probably that's why you didn't notice before upgrading. >>> >>> The 'dc' applet at least requires an executable stack and might be >>> why >>> it is triggered. (Did get a MIPS32-kernel to go crash with 'bad >>> stack' >>> when running dc -e '4 0 / p' however it's fixed in 1.31.0). >>> >>> //M >> OK and I can confirm that I do get the error message on mips64 and >> mips32 (I just failed to notice in my automated test output). >> >> So executable stack is required for floating point on mips? Should I >> send a kernel patch to add && !IS_ENABLED(CONFIG_MIPS) to the warning? >> >>> On 2020-04-23 23:39, Chris Packham wrote: >>>> On Thu, 2020-04-23 at 07:29 +0200, Christophe Leroy wrote: >>>>> Hi, >>>>> >>>>> Christophe >>>>> >>>>> Le 23/04/2020 à 03:13, Chris Packham a écrit : >>>>>> Hi, >>>>>> >>>>>> I'm just in the process of updating our products to Linux v5.6 >>>>>> and >>>>>> one >>>>>> of them produces a new warning message from the kernel about >>>>>> busybox >>>>>> (v1.31.1) >>>>>> >>>>>> kernel: process '/bin/busybox' started with executable stack >>>>> Got similar discussion about klibc 2 monthes ago, look at >>>>> https://lists.zytor.com/archives/klibc/2020-February/004271.html >>>>> >>>>>> The target in question is a mips64 (octeon3). We have other >>>>>> targets >>>>>> (mips32, armv7, ppc32, ppc64) which don't complain. >>>>>> >>>>>> Some searching led me to >>>>>> >>>>>> https://lore.kernel.org/lkml/20191208171918.GC19716@avx2/ >>>>>> >>>>>> Which suggests I should be filing a bug report with the vendor >>>>>> so >>>>>> here >>>>>> I am. >>>>> Did you have a look into busybox bugzilla ? >>>>> https://bugs.busybox.net/ >>>> I did a quick search of the mailing list didn't spot anything >>>> yesterday. >>>> >>>> Just now I did find https://bugs.busybox.net/show_bug.cgi?id=12801 >>>> which is in the ball-park. It points at uclibc + binutils 2.31. I'm >>>> using GNU libc and binutils 2.32. >>>> >>>>>> Here's some readelf output from the binary >>>>> Can you perform "objdump -x " on your binary ? >>>>> >>>> The output is quite large so I'll link to it instead of including >>>> it >>>> in-line. >>>> >>>> https://gist.github.com/cpackham/48eeab4b8801a57ef737e3fda265cae7 >>>> >>>> Interestingly I can't see anything rwx or RWE in either output >>>> >>>> _______________________________________________ >>>> busybox mailing list >>>> busybox@busybox.net >>>> http://lists.busybox.net/mailman/listinfo/busybox _______________________________________________ busybox mailing list busybox@busybox.net http://lists.busybox.net/mailman/listinfo/busybox
